chore: update ssh agent script

Author: nooneknowspeter

scripts/ssh-add-key.sh

@@ -1,4 +1,11 @@
 #!/usr/bin/env bash
 
-eval "$(ssh-agent)"
-ssh-add "$1"
+if [[ "$1" != "" ]]; then
+  eval "$(ssh-agent)"
+  ssh-add "$1"
+fi
+
+echo -e "pass your private ssh-key as an argument:
+\n
+./ssh-add-key.sh ~/.ssh/id_ed25519"
+